Here we go again. Its like Deja Vu.

[#1]

So every year I seem to experience the same problems. As the weather gets warmer, my line speeds start to fall. I know this is normally when weather gets wetter/colder but not in my case. And its happened every year for the last 5 and I dont ever seem to get anywhere with it.

My line started life at 65-67 meg when the SNR was 3db. It got shifted to 6db quite some time ago and my line subsequently dropped to 62-58 meg. 

Anyway, a few weeks back it dropped from 58 to 50, with an SNR of 8db, the next day, still 50 but with 6db. Now this week it has shifted to 48 but still around 6db SNR.

Here's the stats.

Line State:UP [0x0]
Line Mode:G.993.2 (VDSL2)
Line Uptime:18h 21m 37s
Annex:B
Profile:17a
Data Rate:48.940 Mb/s / 14.369 Mb/s
Max. Attainable Data Rate (ATTNDR):51.198 Mb/s / 14.328 Mb/s
Latency:0.13 ms / 0.0 ms
Line Attenuation (LATN):20.1 dB / 24.3 dB
Signal Attenuation (SATN):20.1 dB / 24.3 dB
Noise Margin (SNR):6.8 dB / 5.4 dB
Aggregate Transmit Power (ACTATP):7.7 dB / 13.3 dB
Forward Error Correction Seconds (FECS):0 / 0
Errored seconds (ES):156 / 3965
Severely Errored Seconds (SES):12 / 5
Loss of Signal Seconds (LOSS):15 / 0
Unavailable Seconds (UAS):993 / 993
Header Error Code Errors (HEC):0 / 0
Non Pre-emptive CRC errors (CRC_P):1 / 0
Pre-emptive CRC errors (CRCP_P):0 / 0
ATU-C System Vendor ID:Broadcom 193.144
Power Management Mode:L0 - Synchronized

I know its going to get slower and slower like it does every year. Last year it even dropped below the minimum speed guarantee, but when checked the BTO Engineer said there was no faults and my max attainable was 34 meg. Even though at the time he was here I was connected at 48.

Is there ANYTHING anyone can do? Or am I just stuck in this terrible loop of losing 1/3rd of my speeds and accept there's no faults? My upload was always 19999 @ 6db before all this started too.

[#2]

Hi, did you reset your router?  I think this seems to reset the speed.

[#3]

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@Ballz wrote:

I know its going to get slower and slower like it does every year. Last year it even dropped below the minimum speed guarantee, but when checked the BTO Engineer said there was no faults and my max attainable was 34 meg. Even though at the time he was here I was connected at 48.

Is there ANYTHING anyone can do? Or am I just stuck in this terrible loop of losing 1/3rd of my speeds and accept there's no faults? My upload was always 19999 @ 6db before all this started too.

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What's it say here for the minimum hand back setting. It will also tell you what your line is capable of and usually, what the sync speed was when last checked.

I would be very wary of turning routers etc off too much, as you might get DLM kick in and start limiting the speed.  As for faults, could be a dry joint somewhere. Could be anything. As you've already found out (assuming the Engineer was correct) there is a big difference in the speed that you might be connected at and when OR might get interested i.e. that hand back value. If it is 34Megs, even you running at 35Megs won't get them doing much. 

[#4]

@Ballz

A very interesting post.

In the first instance, if you have not already done so, check your line capability using the BT Wholesale checker, BT Broadband (btwholesale.com). This will tell you

1. Downstream Handback Threshold. If the line drops below this Handback Threshold Mbps you can request that Openreach investigate.
2. If the line has a bridge tap.
3. When the line was last tested.

Have you checked out your line for noise by running the “quiet line” test?  

To do this dial 17070 - option 2 using a corded handset if possible - the only sound you should hear is a periodic 'Quiet Line Test' voice message.

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@Ballz wrote:

My line started life at 65-67 meg when the SNR was 3db. It got shifted to 6db quite some time ago and my line subsequently dropped to 62-58 meg. 

I believe that this happens when G.IMP is turned off. Lines that run at or around SNR=3dB have G.IMP turned on. SNR=6dB was the old lower limit before G.IMP was implemented.

Why is G.IMP turned off?

Could be a modem or DSLAM issue or perhaps you have too much line noise thus making G.IMP ineffective. You report that the issue is seasonal; so I’m inclined to think line noise.

Your modem reports: Severely Errored Seconds (SES):12 / 5.

Both the downstream and upstream figures are high. Suggesting a line noise issue. As the noise issue gets worse the DLAM’s DLM will manage the line bps down to reduce the error rate.

It would be interesting to have modem stat reports for the “winter season” in addition to the “spring season” in the OP.

I note that your modem uses a Broadcom chip set. There is an app called DSLstats that will Telnet to your modem and gather bit allocations to the transmission bins (frequencies). This can tell us which transmission bins are being impacted and consequently which frequencies are “noisy”.

Do you know if your line is serviced by an Openreach cabinet supplied by Huawei or ECI? It is generally believed that ECI cabs have grounding issues that make them more susceptible to noise.

Back to seasonality. I’m thinking of an environmental noise source that is getting into your line. Seasonality is the clue. Do you know the location of your Openreach cabinet?  Can you think of, or see, in the vicinity any potential noise source e.g. manufacturing/processing site that may be “quiet” in the winter? Is there a difference of equipment use in your home?

If noise (REIN, RFI, SHINE, EMI) is the issue, finding the cause will require work and patience. Openreach will avoid getting drawn in unless line performance consistently drops below the Handback Threshold as diagnosing is time consuming.

[#5]

Thanks for the informative posts. I do understand how DLM works. My cabinet is ECI. 

Nothing near the cabinet changes seasonally, and I have done quiet line tests and they seem fine. 

As said before It did sit at 62-63 for quite some time after the shift it made to 6db, now it seems every few days im dropping another meg. 

Your broadband service

• Product: Unlimited Fibre Extra
• Estimated Download Range: 42 - 62Mbps
• Estimated Upload Range: 9 - 14Mbps
• Minimum Guaranteed Speed: 36.4Mbps
• Current Line Speed (Download): 47.2Mbps

The above did change, when I opted to take the exit route after it dropped below my minimum previously (42 meg) I then faced the issue of "nobody could offer me any faster anyway". So I decided to stay with plusnet, but the minimum speed guarantee dropped to 36 after the new contract was started, so i ended up in a worse situation.

I just dont understand how it can be fine for over a year, then suddenly starts to drop 1/3rd of its speed and it not be a problem. If I bought a car from a garage and after a year it didnt go as fast as it did before I would be taking it to the garage to get it repaired. A few meg either way I understand might be lost, but 12+ meg downstream and 6 meg upstream?

[#6]

Hi, sorry if late to the party...but have you retested following modem reset? (To eradicate modem issues which seem to be very common).

[#7]

I have 3 routers, all 3 connect at the same speeds. Im not one to reset my router too many times. I was using a TP Link W9980 for the last 3 years, I did think that maybe the router was playing up so I flashed my old hub with OpenWRT, Setup and installed that 2 weeks ago. Since then the connection has been a lot more stable. Previously I was disconnecting daily, but since using OpenWRT its been a lot better. Still no faster though.

[#8]

DSL Status
Line State:UP [0x0]
Line Mode:G.993.2 (VDSL2)
Line Uptime:1d 1h 7m 36s
Annex:B
Profile:17a
Data Rate:48.940 Mb/s / 14.089 Mb/s
Max. Attainable Data Rate (ATTNDR):51.870 Mb/s / 14.074 Mb/s
Latency:0.13 ms / 0.0 ms
Line Attenuation (LATN):20.2 dB / 24.4 dB
Signal Attenuation (SATN):20.0 dB / 24.2 dB
Noise Margin (SNR):6.9 dB / 5.7 dB
Aggregate Transmit Power (ACTATP):7.8 dB / 13.0 dB
Forward Error Correction Seconds (FECS):0 / 0
Errored seconds (ES):156 / 4001
Severely Errored Seconds (SES):12 / 5
Loss of Signal Seconds (LOSS):17 / 0
Unavailable Seconds (UAS):1026 / 1026
Header Error Code Errors (HEC):0 / 0
Non Pre-emptive CRC errors (CRC_P):1 / 0
Pre-emptive CRC errors (CRCP_P):0 / 0
ATU-C System Vendor ID:Broadcom 193.144
Power Management Mode:L0 - Synchronized

Here's another stats copy from right now. Loss of signal and UAS have both increased a little, but It hasnt dropped out. Errored seconds seems to have increased too.

[#9]

Reading all the above it does seem that you have an impacted line i.e. even your guaranteed min speed is based on an impacted service. Maybe you have aluminium cables in the mix. As you seem pretty well clued up on all the ins and outs already, sadly it looking like a case of doing what you've done before or living with it until something better comes along. Not ideal at all.

Annoying as it is, unfortunately until you really do start to get down to 36Mb, you won't get much sense out of OR. Their take - Problem? What problem! Good luck.

[#10]

No aluminium here, on the next estate across that is a thing. Here its all old copper. My OR engineer friend said he would put me a new cable across from the pole. Trouble is the pole has a Red D mark, which means it cannot be climbed and required a bucket to work on it.